Particulate Material Delivery System For Variable Rate Sectional Control

ABSTRACT

A particulate material delivery system is provided that allows for variable rate sectional control while delivering particulate material to an agricultural field. The system may include an air cart and a drill that are towable behind a tractor and that includes a metering system receiving product from the air cart and delivering the product to the drill for distribution to the ground, such as an agricultural field. The metering system includes multiple metering units that receive separate portions of the product from the air cart. Multiple prime movers drive the multiple metering units. A controller is connected to and individually controls the multiple prime movers such that distribution rates of the multiple metering units can be varied independently of each other.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Ser. No. 61/589,565filed Jan. 23, 2012.

FIELD OF THE INVENTION

The invention relates generally to agricultural systems and, inparticular, to particulate material delivery systems that use an aircart-type implement(s) for pneumatically distributing product such asfertilizer and small grains.

BACKGROUND OF THE INVENTION

Modern large acreage seeding implements pneumatically deliver seed,fertilizer, and/or other product to fields. An example is an air cartand an air drill that are pulled together behind a tractor to deliverproduct. Different seeding styles can be implemented by using differentopeners on the air drills. Knife, ribbon band, ribbon band sweep,double-shoot, and disk openers can be used for different seeding stylesthat can open correspondingly different styles of furrows to receive theseed. The air cart pneumatically conveys seed to the air drill fordelivery into the furrow(s). Air carts include one or more storagecompartments that hold product(s), each of which has an associatedmetering box. The metering box divides product(s) from the associatedstorage compartment(s) into equal sections for delivery of equal productvolumes. The equally divided product(s) is entrained in an airflowestablished by a fan and delivered through manifolds and distributionlines that direct the product from the air cart, to the air drill, andto the field being planted with seed.

SUMMARY OF THE INVENTION

The present invention is directed to a particulate material deliverysystem that allows for variable rate sectional control while deliveringparticulate material to an agricultural field. The system may beincorporated with air carts and air drills, and that includes a meteringsystem having multiple metering units that are independentlycontrollable. This may allow for individual controlling product deliveryrates through metering units so as to independently control the deliveryrate(s) to each of multiple secondary distribution headers or manifolds,which may allow for sectional control of product delivery from the airdrill.

According to one aspect of the present invention, a particulate materialdelivery system is provided that may include an air cart and a planterthat are towable behind a tractor. A metering system of the particulatematerial delivery system receives a product from the air cart anddelivers the product to the planter for distribution to the ground, suchas an agricultural field. The metering system may include multiplemetering units that receive separate portions of the product from theair cart. Multiple prime movers may drive the multiple metering units. Acontroller is connected to and individually controls the multiple primemovers such that distribution rates of the multiple metering units canbe varied independently of each other. The multiple prime movers may beelectric motors.

According to another aspect, each of the multiple metering units mayinclude a metering roller, and a shaft that supports and rotates themetering roller. The electric motors may directly drive ends of theshafts that support the metering roller.

According to another aspect, each of the multiple metering units mayinclude a metering roller having an external gear at an outercircumferential surface thereof. Each electric motor may directly drivethe external gear of a respective metering roller.

According to another aspect, each of the multiple metering units mayinclude a metering roller having an internal gear at an innercircumferential surface thereof. Each electric motor may directly drivethe internal gear of a respective metering roller.

According to another aspect, an airflow characteristic of an airflowthat entrains the product may be controlled based on a delivery rate ofat least one of the multiple metering units for pneumatically conveyingproduct from the multiple metering units toward multiple opener units ofthe drill. The delivery rate of the product to multiple locations of theagricultural field may be individually controlled by controlling thedelivery rate of product through each of the multiple metering units andcontrolling the airflow characteristic. This may allow for providing aparticulate material delivery system that provides delivery consistencyand control without requiring singulation-type equipment such asrow-unit planters, which may provide a relatively simple andcost-effective air-seeder-type particulate material delivery system witha high amount of delivery accuracy. This may allow for delivery ratevariability at secondary headers or manifolds of a single drill whichallows for site specific precision farming. This may also allow forrelatively more application precision by way of variable rate sectionalcontrol of a drill as compared to typical drills that each typicallyallows for delivery rate variability of only the whole drill.

Other aspects, objects, features, and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription and accompanying drawings. It should be understood, however,that the detailed description and specific examples, while indicatingpreferred embodiments of the present invention, are given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention are illustrated in theaccompanying drawings in which like reference numerals represent likeparts throughout.

FIG. 1 is a simplified pictorial view of a particulate material deliverysystem in accordance with the present invention;

FIG. 2 is a side elevation view of a portion of a variant of theparticulate material delivery system of FIG. 1;

FIG. 3 is a perspective view of a metering system used in theparticulate material delivery system of FIG. 2 with the meteringcartridge partially removed;

FIG. 4 is an exploded view of a metering unit of the metering system ofFIG. 3;

FIG. 5 is an exploded view of a variant of the metering unit of FIG. 4;

FIG. 6 is a schematic sectional representation of a metering systemincorporating the metering unit of FIG. 5;

FIG. 7 is schematic representation of another variant of the meteringunit of FIG. 4;

FIG. 8 is a perspective view of a metering system according to anotherembodiment of the invention;

FIG. 9 is a perspective view of a variant of the metering system of FIG.8; and

FIG. 10 is a perspective view of another variant of the metering systemof FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an agricultural particulate material deliverysystem 5 is shown that includes a tractor 8, an air cart 10 that maydefine a seed cart and which is shown as an air cart such as a PRECISIONAIR® cart available from the Case IH company, and a drill 12, which isshown as an air drill such as an ATX700 air hoe drill available from theCase IH company. The air cart 10 and the drill 12 are hitched to thetractor 8 and/or each other in a conventional manner. A pneumaticdistribution system 14 is arranged with respect to the air cart 10 andthe drill 12 for pneumatically delivering product 16 from the air cart10 to the drill 12 for pneumatic distribution of the product to anagricultural field. The product 16 is a particulate material that may beseed such as small grains and/or fertilizer such as dry granularfertilizer. Referring now to FIG. 2, the pneumatic distribution system14 includes a fan(s) 18, which may be a centrifugal fan, for generatingan airflow(s) that is directed through the pneumatic distribution system14 to entrain product 16 for pneumatic delivery to the agriculturalfield.

Referring to FIGS. 1 and 2, the air cart 10 includes a frame 20 to whichstorage compartments 22 and wheels 24 are mounted. Each storagecompartment 22 has an associated metering system 26 (FIG. 2) arranged atits lower end for receiving product 16 from the storage compartment 22.Each metering system 26 is configured for segmented control thereof toallow for controlled feeding of product 16 into the airflow(s) generatedby the fan(s) 18 so that product 16 may be distributed at differentdelivery rates to different portions of the drill 12 by way ofcontrolling how much product 16 is delivered into separate segments ofor in fluid communication with the primary distribution manifold 30 forcontrolled variation of delivery rate of the product 16 to differentlocations on the agricultural field. The airflow(s) from the fan(s) 18is directed by a plenum 28 to a primary distribution manifold 30 thatincludes individual passages which divide the airflow into separateairflows or airflow segments that are each connected by a firstdistribution line(s), shown as primary distribution lines 32 that extendtoward the drill 12.

The drill 12 includes a frame 34 to which a set of opener units 36 iscoupled. FIG. 1 shows disc-style opener units 36, whereas FIG. 2 showstip-type opener units 36. The opener units 36 are configured to cut afurrow into the soil. A secondary distribution manifold(s) 38 isarranged on the drill 12 and is respectively connected to the primarydistribution line(s) 32. A second distribution line(s), shown assecondary distribution lines 40, connects the secondary distributionmanifold 38 to individual outlets for delivery of seed at each furrowcreated in the agricultural field by each opener unit 36, allowing thepneumatic distribution system 14 to pneumatically deliver the product 16from the air cart 10 into the furrows cut by the opener units 36. Seedrow finishing equipment such as wheel packers or closing wheels 42 maybe arranged on the drill 12, such as the embodiment shown in FIG. 2foreclosing the furrow(s).

Referring now to FIGS. 2 and 8, each metering system 26 includes ahousing 44 in communication with the storage compartment 22. Referringnow to FIGS. 3 and 8, product 16 (FIG. 1) from the storage compartment22 is directed to the housing 44 where it is divided between anddelivered to multiple individually controlled metering units 46,explained in greater detail elsewhere herein. The metering units 46 areindividually driven by separate prime movers 48 so that individualmetering rollers 50 of the individual metering units 46 can each berotated at variable speeds. Each prime mover 48 may be, for example, ahydraulic motor, but is preferably an electric motor and, morepreferably, a 12V DC electric motor. Conductors 52 operatively connecteach prime mover 48 to a controller 54 and a power supply 56 (FIGS. 3,4, and 6) which can be electrically connected to the 12V DC electricalsystem of the tractor 8. The controller 54 is further operativelyconnected, in a conventional manner, to any of a variety of suitablesensors for sensing, e.g., travel velocity of the air cart 10, and/orother operating characteristics and which allows for automatic controlof the system 5 by way of the controller 54 for variable rate sectionalcontrol while delivering the product 16 to the agricultural field. Thecontroller 54 can include an industrial computer or, e.g., aprogrammable logic controller (PLC), along with corresponding softwareand suitable memory for storing such software and hardware, includinginterconnecting conductors for power and signal transmission forcontrolling electronic, electro-mechanical, or other components of thepneumatic distribution system 14 and/or metering system 26. Thecontroller 54 can evaluate the operating characteristics of theparticulate material delivery system 5 or its components to determinethe desired delivery rate of product from each of the metering units 46and, thus, product delivery rate from each of multiple portions of thedrill 12. The controller 54 controls the particular speed at which eachmetering roller 50 is driven and, thus, rates at which product isdelivered may be varied as a function of the operating conditionsincluding, but not limited to, the ground speed or travel velocity ofthe air cart 10, the length of the distribution lines 32 or 40, or thetopology of the field, such as a curved row. In one embodiment, thecontroller 54 controls the fan 18 to vary the fan rotational speed,e.g., increase or decrease, and correspondingly vary the air flowcharacteristics such as mass flow rate or volume based on the deliveryrate variation of the metering units 46, so as to, for example, matchair flow rate with product delivery rate. In another embodiment, thecontroller 54 varies the air flow rate by actuating a damper 58 (FIG. 6)that regulates flow rate in each of the plenums 28 in addition to or inlieu of varying the fan speed of fan 18. Controller 54 can individuallycontrol actuation of the dampers 58 by, for example, energizingrespective actuators 60 so that different airflow rates can be providedthrough the different plenums 28 while all being supplied from a singlefan 18. Regardless of the particular controlling parameters, eachmetering unit 46 of the metering system 26 may be directly driven by theprime mover 48 by way of one of an internal drive arrangement withrespect to the metering roller 50, and external drive arrangement withrespect to the metering roller 50, or an end-shaft driving arrangementwith respect to the roller 50, as explained in greater detail elsewhereherein.

Referring now to FIG. 3, the metering system 26 of this embodimentdefines a cartridge-type configuration, represented as a cartridge 62that is defined by multiple adjacent metering units 46. As shown inFIGS. 4 and 5, each metering unit 46 is mounted adjacent to anothermetering unit 46 via bolts 64 passing through opening 66 in eachmetering unit 46. Within the cartridge 62, each metering unit 46 mayrelease product 16 (FIG. 1) for delivery to an individual row of thedrill 12 or each metering unit 46 may release product 16 for delivery tomultiple rows of the drill 12. Referring again to FIG. 3, the housing 44in which the cartridge 62 is arranged in this embodiment has an uppersurface 68 coupled to the storage compartment 22 (FIG. 2) and a lowersurface 70 coupled to the primary distribution manifold 30 (FIG. 2). Aninlet passage 72 is defined in the upper surface 68 through whichproduct 16 (FIG. 1) is received from the storage compartment 22 into thehousing 44.

Referring now to FIGS. 4 and 5, each metering unit 46 includes a housing47 with an intake 74 in communication with the housing inlet passage 72and an exit 76 through which the product 16 passes to the primarydistribution manifold 30. The metering roller 50 of each metering unit46 is arranged between the intake 74 and exit 76 and may be supported bya shaft 78 extending concentrically through the metering roller 50. Themetering roller 50 defines a drum-like shape and includes multiplecompartments 80 arranged at an outer circumferential surface of themetering roller 50, shown as extending into the outer circumferentialsurface. The compartments 80 are sized to convey and control the volumeand rate of product transferred through the metering unit 46 fordelivery out of the exit 76 to be entrained in the airflow of andcarried through the primary distribution lines 32 toward the drill 12for delivery to the agricultural field.

Referring next to FIG. 4, an embodiment of the metering unit 46 in whichthe metering roller 50 is internally driven is illustrated. In theillustrated embodiment, a single metering unit 46 is shown with theprime mover 48 that is aligned with and mounted directly to the shaft78. An output shaft 82 of the prime mover 48 extends through an axialbore of the shaft 78. The shaft 78 may further include a retainingmember within the shaft 78, such as a clip or a hole extending throughthe shaft 78 through which a retaining member, such as a screw or bolt,may be passed, securing the prime mover output shaft 82 within the shaft78. The prime mover output shaft 82 may be oriented within the shaft 78such that an output shaft end 84 extends beyond the shaft 78. An outputgear 86 is then mounted on the output shaft end 84, external to theshaft 78. A metering gear 88 is arranged within the metering roller 50and defines a tooth inner circumferential surface of a flange 90 at anend of the metering roller 50 which is driven by rotation of the outputgear 86. The output gear 86 may occupy the entire space within themetering gear 88 such that the output and metering gears 86, 88 define asplined-type engagement for a one-to-one drive ratio, or the output gear86 may be smaller than the metering gear 88 to provide other driveratios. In one embodiment, an intermediate gear(s) may be arrangedbetween the output gear 86 and metering gear 88 to provide the desireddrive ratio. The conductors 52 may extend out the end of the shaft 78opposite the end from which the output shaft end 84 extends andoperatively connect the prime mover 48 to the controller 54 and thepower supply 56.

Referring now to FIGS. 5 and 6, in this embodiment, an embodiment of themetering unit 46 in which the metering roller 50 is externally driven isillustrated. The metering unit 46 and its components are substantiallyidentical as that described with respect to FIG. 4. Accordingly, thosedescriptions are applicable here with respect to the metering unit 46shown in FIGS. 5 and 6. The difference is that instead of beinginternally driven, the metering roller 50 of FIGS. 5 and 6 is externallydriven. Accordingly, the metering gear 88 is provided outside of or atan outer circumferential surface of the flange 90 at the end of themetering roller 50. The prime mover 48 is not axially aligned with theshaft 78 but is instead transversely spaced from the shaft 78. Theoutput gear 86 of the prime mover 48 is radially aligned with themetering gear 88. As illustrated, the output gear 86 can directly engagethe metering gear 88; optionally, an intermediate gear(s) may beprovided therebetween.

Referring next to FIG. 7, in this embodiment, an embodiment of themetering unit 46 in which the metering roller 50 is end-shaft driven isillustrated. The metering unit 46 and its components are substantiallyidentical as that described with respect to FIG. 4. Accordingly, thosedescriptions are applicable here with respect to the metering unit 46shown in FIG. 7, although being shown in a more simplified and schematicrepresentation. The difference is that instead of being internallydriven, the metering roller 50 of FIG. 7 is driven directly by an end ofthe output shaft of the prime mover 48. Accordingly, a metering gear 88is not required in this embodiment. Instead, the output shaft 82 of theprime mover 48 is axially aligned with and connected to the center ofthe flange 90, shown as being circular, at an end of the metering roller50. In another embodiment of the end-shaft driven arrangement, the shaft78 is fixed to the metering roller 50 so that the shaft 78 and meteringroller 50 rotate in unison with each other. In such embodiment, theoutput shaft 82 of the prime mover 48 may be coupled to and rotates anend of the shaft 78 of the metering roller 50, either as an end-to-endaxial coupling or through one or radially intermediate gears.

Referring next to FIG. 8, unlike the embodiment of FIG. 3, in thisembodiment, the housing 44 of the metering system 26 is constructed inmultiple housing segments 92. Each housing segment 92 of this embodimentincludes, for example, an upper portion 94 to receive product 16(FIG. 1) from the storage compartment 22 and a lower portion 96 thatextends between and connects the upper portion 94 and a primarydistribution line 32. The metering units 46 in FIG. 8 are substantiallyidentical to metering units 46 described above with respect to FIGS.3-7. Accordingly, the description of such metering units 46 and theircomponents in FIGS. 3-7 is applicable here with respect to the meteringunits 46 shown in FIG. 8. However, unlike the metering units 46 of FIGS.3-7, the metering units 46 of FIG. 8 are not interconnected with eachother to define a cartridge 62. Instead, the metering units of 46 ofFIG. 8 are separately arranged in respective ones of the housingsegments 92, shown here as arranged in the upper portions 94 of thesegments 92. This arrangement permits access to individual meteringunits 46 for repair and/or exchange without removing all of the meteringunits 46 from their respective individual mountings with the otherhousing segments 92.

Still referring to FIG. 8, the metering units 46 separately receiveproduct 16 through the upper portions 94 of the housing segments 92 andmeter out the product 16 through the lower portions 96 by rotating themetering rollers 50 to deliver the product 16 into the airflows flowingthrough the primary distribution line 32 in a controlled manner. Threedifferent exemplary arrangements for driving the metering rollers 50 ofthe metering units 46 with the prime movers 48 are shown in FIG. 8.These are (i) an external driving arrangement shown at the left-mostmetering unit 46, (ii) an end-shaft driving arrangement shown at themiddle metering unit 46, and (iii) an internal driving arrangement shownat the right-most metering unit 46.

Still referring to FIG. 8, the external driving arrangement at theleft-most metering unit 46 may be a substantially identical arrangementto that shown in FIGS. 5 and 6, whereby the description of the meteringunit 46 in FIGS. 5 and 6 is applicable here with respect to theleft-most metering unit 46 of FIG. 8. The left-most metering unit 46 ofFIG. 8 and with reference to FIGS. 5 and 6, the prime mover 48 istransversely spaced with the central axis of the metering roller 50.Such metering unit 46 is arranged with the prime mover 48 driving anouter rim, for example, a metering gear 88, of the metering roller 50 byengaging teeth at the outer circumferential surfaces of the meteringroller 50 and output gear 86 of the prime mover 48.

Referring again to FIG. 8, the end-shaft driving arrangement of themetering unit 46 shown in the middle may be a substantially identicalarrangement to that shown in FIG. 7, whereby the description of themetering unit 46 in FIG. 7 is applicable here with respect to the middlemetering unit 46 of FIG. 8. The middle metering unit 46 of FIG. 8 andwith reference to FIG. 7 includes an output shaft 82 that is generallyaxially aligned with and coupled to the flange 90 at an end of themetering roller 50, or a shaft 78 extending concentrically through forrotating the metering roller 50.

Referring again to FIG. 8, the internal driving arrangement at theright-most metering unit 46 may be a substantially identical arrangementto that shown in FIG. 4, whereby the description of the metering unit 46in FIG. 4 is applicable here with respect to the right-most meteringunit 46 of FIG. 8. The right-most metering unit 46 of FIG. 8 and withreference to FIG. 4 is arranged so that the output gear 86 of the primemover 48 engages and drives an inner circumferential surface of ametering gear 88 of the metering roller 50.

Referring now to FIGS. 9 and 10, like the embodiment of FIG. 8, thehousing 44 of the metering system 26 in each of these embodimentsincludes multiple housing segments 92 that individually deliver product16 to the individual metering units 46. Referring to FIG. 9, the housing44 has housing segments 92 that are transversely aligned with andadjacent to each other and the metering roller(s) 50 may be arrangedparallel to the primary distribution line(s) 32, only one shownschematically, that receives the product 16 (FIG. 1) from the meteringunit. Referring to FIG. 10, the housing 44 has housing segments 92 thatare generally longitudinally aligned with each other and transverselystaggered. In this way, the prime mover 48 of one metering unit 46 mayextend under a housing segment 92 of an adjacent metering unit 46, andthe metering roller(s) 50 may be arranged perpendicular to the primarydistribution line(s) 32.

In light of the above, during use, the product 16 (FIG. 1) is receivedfrom the storage compartment(s) 22, through the inlet passage 72, intothe housing 44 of the metering system 26. Simultaneously, an opener unit36 opens a trough or furrow in the agricultural field to receive theproduct 16. The prime mover 48 rotates the metering roller 50 at each ofthe metering units 46. As the metering roller 50 rotates past the intake74 of the metering unit 46, product fills each compartment 80. As themetering roller 50 rotates past the exit 76 of the metering unit 46, theproduct empties from each compartment 80 into the primary distributionmanifold 30 or a primary distribution line(s) 32 of the pneumaticdistribution system 14 to be distributed to each of the furrows openedby the opener units 36. As the drill 12 advances further, the closingwheels 42 close each furrow with the product therein.

All the while, the controller 54 monitors numerous operating conditionsto determine the proper rotational speed of each metering roller 50,optionally, to determine the proper fan rotational speed of fan 18and/or position of damper 58 (FIG. 6) to achieve a proper airflow ratefor each of the metering units 46. In this way, the controller 54 mayindividually control delivery rates of the multiple metering units 46,independently of each other, as well as individually control an airflowcharacteristic of an airflow for each of the multiple metering units 46.The controller 54 may be configured to automatically control themultiple metering units 46 independently of each other and/or airflowcharacteristics so as to provide variable rate sectional control whiledelivering the product 16 to the agricultural field. This allows thecontroller 54 to separately control delivery rate of product 16 to atleast some of the multiple locations of the agricultural field, forexample, corresponding to locations of the opener units 36, which may bedone automatically. This may be done by the controller 54 individuallycontrolling the delivery rate of product 16 through each of the multiplemetering units 46, and which may include individually controlling anairflow characteristic of an airflow for each of the multiple meteringunits 46 such that airflows entraining product from the multiplemetering units 46 are each controlled based on the delivery rate of therespective one of the multiple metering units 46. In one embodiment, theairflow characteristic(s) may be controlled based on a delivery rate ofmore than one of the metering units 46. Furthermore, the airflowcharacteristic(s) may be controlled based on a delivery rate of ametering unit 46 that has a greatest delivery rate when compared to theother metering units 46. In one embodiment, the rotational speed may bea function of the ground speed or travel speed of the drill 12 and adesired seed depositing rate from the seed metering system 26. Thus, asthe tractor 8 and, consequently, the drill 12 increases or decreasesspeed, the controller 54 may correspondingly increase or decrease thecommanded rotational speed of each of the output shafts 82 of the primemovers 48 and, thus, the metering rollers 50, optionally, air flow rateby way of damper 58 and/or rotational speed of fan 18, to maintain aconsistent seed depositing rate. Similarly, certain ground conditionsmay require an increase or a decrease in the seed depositing rate of themetering rollers 50. Therefore, even if the tractor 8 maintains auniform speed, the controller 54 may monitor the ground conditions, forexample, via sensors or from a preprogrammed map and a globalpositioning system (GPS) coordinate, to adjust the rotational speed ofthe drive mechanisms as a function of the ground conditions.Accordingly, the seed metering system 26 receives commands for eachmetering unit 46, preferably, at a variable rate and, more preferably,at an infinitely variable rate, based at least in part on the groundspeed or the drill 12 or the ground conditions.

Furthermore, in one embodiment, a single controller 54 controls all ofthe metering units 46. Doing so can ensure that each metering unit 46receives the same control signals, whereby the resultant outputresponses should be substantially analogous, when that is desired. Thiscan enhance uniformity of seed placement between the individual rows andother operating characteristics.

However, controller 54 can also provide separate rotational speedcommands to each individual metering unit 46 independently of the otherspeed commands and other metering unit(s) 46. In such configuration,each metering unit 46 can be activated and deactivated independently ofeach other, whereby overplanting can be managed and minimized.Accordingly, when using row crop planting techniques such as, e.g.,planting point rows, turn rows, headland rows, or end rows, or in othersituations which could lead to double planting or other overplantingconditions, the operator or controller 54 can de-energize and thusdisengage any one or more of the individual metering units 46, asdesired. This enables the user and/or controller 54 to comprehensivelymanage the application of seed, on a per-row planting unit and, thus,per-row basis. As still another option, multiple controllers 54 maymonitor conditions and provide rotational speed or other commands to aportion of the metering units 46.

It is further contemplated that varying rotational speed commands may beprovided to metering units 46 according to which row on the drill 12 therespective metering unit(s) 46 is connected. For example, outer rowsrequire longer secondary distribution lines 40 than central rows. Thus,the time required for product to travel from the metering system 26 tothe outlet of each row on the drill 12 varies. Further, air pressurevariation as a function of the length of the distribution lines, 32 and40, may result in varying dispersal rates at the outlet of each row.Thus, the controller 54 may provide varying rotational speed commands tometering units 46 at particular rows on the drill 12 to produce auniform output at the outlets of each row on the drill 12 and a uniformdispersion to the ground.

In addition, the controller 54 may vary, for example, automaticallyvary, the rotational speed commands to each metering unit 46 during aturn. As the tractor 8 and, subsequently, the drill 12, turn a corner,those rows along the inner radius of the turn travel a shorter distancethan those rows along the outer radius of the turn. Thus, the controller54 may increase the rotational speed command to prime movers 48 ofmetering units 46 supplying product to outer rows, decrease therotational speed command to drive the prime movers 48 of metering units46 supplying product to inner rows, or a combination thereof. Controller54 may vary the rotational speed of fan 18 and/or the position of thedamper 58 so as to vary the air flow characteristic(s) accordingly.

It should be understood that the invention is not limited in itsapplication to the details of construction and arrangements of thecomponents set forth herein. The invention is capable of otherembodiments and of being practiced or carried out in various ways.Variations and modifications of the foregoing are within the scope ofthe present invention. It also being understood that the inventiondisclosed and defined herein extends to all alternative combinations oftwo or more of the individual features mentioned or evident from thetext and/or drawings. All of these different combinations constitutevarious alternative aspects of the present invention. The embodimentsdescribed herein explain the best modes known for practicing theinvention and will enable others skilled in the art to utilize theinvention.

We claim:
 1. A particulate material delivery system comprising: an aircart and a drill that are towable behind a tractor; a metering systemreceiving a product from the air cart and delivering the product to thedrill for distribution to an agricultural field, the metering systemincluding, multiple metering units receiving separate portions of theproduct from the air cart; multiple prime movers driving the multiplemetering units; and a controller connected to and individuallycontrolling the multiple prime movers for controlling distribution ratesof the multiple metering units independently of each other.
 2. Theparticulate material delivery system of claim 1 wherein the multipleprime movers are electric motors.
 3. The particulate material deliverysystem of claim 2 wherein each of the multiple metering units includes ametering roller, and a shaft that supports and rotates the meteringroller, and wherein each electric motor drives an end of the shaft thatsupports a respective metering roller.
 4. The particulate materialdelivery system of claim 2 wherein each of the multiple metering unitsincludes a metering roller having an external gear at an outercircumferential surface thereof, and wherein each electric motordirectly drives the external gear of a respective metering roller. 5.The particulate material delivery system of claim 2 wherein each of themultiple metering units includes a metering roller having an internalgear at an inner circumferential surface thereof, and wherein eachelectric motor directly drives the internal gear of a respectivemetering roller.
 6. The particulate material delivery system of claim 1further comprising a fan the provides an air flow in which product isentrained for distribution to the agricultural field, the controlleroperatively connected to and controlling a speed of the fan based on thedistribution rate of at least one of the multiple metering units.
 7. Theparticulate material delivery system of claim 1 further comprising apneumatic distribution system arranged with respect to the air cart andthe drill for pneumatically delivering the product from the air cart tothe drill for pneumatic distribution to the agricultural field.
 8. Theparticulate material delivery system of claim 7 wherein the air cartdefines a seed cart and the drill defines an air drill cooperating withthe pneumatic distribution system for entraining the product in at leastone airflow for continuous pneumatic conveyance of the product from themetering system to the agricultural field.
 9. A particulate materialdelivery system comprising: an air cart towable behind a tractor anddefining an air cart for bulk storage of a product to be pneumaticallydistributed to an agricultural field; a drill towable behind a tractorand defining an air drill engaging the agricultural field and forpneumatic delivery of the product to the agricultural field; a pneumaticdistribution system arranged with respect to the air cart and the airdrill for pneumatically delivering the product from the air cart to thedrill for pneumatic distribution to the agricultural field, thepneumatic distribution system including a primary distribution manifoldfor separating an airflow into multiple airflows through the pneumaticdistribution system, multiple primary distribution lines extending fromthe primary distribution manifold for conveying the respective multipleairflows from the primary distribution manifold and product entrained inthe respective airflows, multiple secondary distribution manifoldsarranged to receive product from respective primary distribution lines,and multiple secondary distribution lines extending from each of thesecondary distribution manifolds and arranged for pneumatic delivery ofthe product to the agricultural field; a metering system arrangedbetween the air cart and the pneumatic distribution system and receivingproduct from the air cart and for controlled release of the product intothe pneumatic distribution system; the metering system including,multiple metering units receiving separate portions of the product fromthe air cart and arranged for separate delivery to respective ones ofthe primary distribution lines; multiple prime movers driving themultiple metering units; and a controller connected to and individuallycontrolling the multiple prime movers for controlling distribution ratesof the multiple metering units independently of each other forindividually controlling product delivery rate to the secondarydistribution manifolds so as to provide individual control of deliveryof product from different segments of the air drill.
 10. The particulatematerial delivery system of claim 9 wherein the primary distributionmanifold is arranged upon the air cart and each of the secondarydistribution manifolds is arranged upon the air drill.
 11. Theparticulate material delivery system of claim 10 wherein the multipleprime movers are electric motors.
 12. The particulate material deliverysystem of claim 11 wherein each of the multiple metering units includesa metering roller, and a shaft that supports and rotates the meteringroller, and wherein each electric motor directly drives an end of theshaft that supports a respective metering roller.
 13. The particulatematerial delivery system of claim 11 wherein each of the multiplemetering units includes a metering roller having an external gear at anouter circumferential surface thereof, and wherein each electric motordirectly drives the external gear of a respective metering roller. 14.The particulate material delivery system of claim 11 wherein each of themultiple metering units includes a metering roller having an internalgear at an inner circumferential surface thereof, and wherein eachelectric motor directly drives the internal gear of a respectivemetering roller.
 15. The particulate material delivery system of claim10 further comprising a fan the provides an air flow in which product isentrained for distribution to the agricultural field, the controlleroperatively connected to and controlling a speed of the fan based on thedistribution rate of at least one of the multiple metering units.
 16. Amethod of using a particulate material delivery system to pneumaticallydispense seed to an agricultural field, the method comprising:delivering product from a storage compartment to a metering systemhaving multiple metering units; individually controlling the deliveryrate of product through each of the multiple metering units; controllingan airflow characteristic of an airflow that entrains the product basedon the delivery rate of at least one of the multiple metering units forpneumatically conveying product from the multiple metering units towardmultiple opener units of the drill for delivering product at multiplelocations of an agricultural field corresponding to the locations of themultiple opener units of the drill; and separately controlling deliveryrate of the product to at least some of the multiple locations of theagricultural field by individually controlling the delivery rate ofproduct through each of the multiple metering units and controlling theairflow characteristic.
 17. The method of claim 16 further comprisingindividually controlling an airflow characteristic of an airflow foreach of the multiple metering units such that airflows entrainingproduct from the multiple metering units are each controlled based onthe delivery rate of the respective one of the multiple metering units.18. The method of claim 16 further comprising controlling the airflowcharacteristic based on a delivery rate of more than one of the meteringunits.
 19. The method of claim 16 further comprising controlling theairflow characteristic based on a delivery rate of a first metering unitthat defines a greater delivery rate than the other metering units. 20.The method of claim 19 wherein the multiple prime movers are electricmotors.